• Scientists say that about half of this historic drought can be blamed on man-made global warming.
• The study covers an area stretching across nine U.S. states from Oregon down to New Mexico.
• Naturally-occurring western megadroughts have occurred many times before.

Fueled in part by human-caused climate change, a “megadrought” appears to be emerging in the western U.S., a study published Thursday suggests.

In fact, the nearly-20-year drought is almost as bad or worse than any in the past 1,200 years, scientists say.

Megadroughts – defined as intense droughts that last for decades or longer – once plagued the Desert Southwest. Thanks to global warming, an especially fierce one appears to be coming back:

“We now have enough observations of current drought and tree-ring records of past drought to say that we’re on the same trajectory as the worst prehistoric droughts,” said study…